Monographs Details: Mimosa venatorum Barneby
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1991. Sensitivae Censitae. A description of the genus Mimosa Linnaeus (Mimosaceae) in the New World. Mem. New York Bot. Gard. 65: 1-835.
Synonyms:Mimosa pyrenea Taub., Mimosa papposa Benth., Mimosa urbaniana Glaz.
Description:Species Description - Slender, distantly foliate unarmed subshrubs (3-)4-l 0 dm, the erect or stiffly ascending, simple or few-branched stems ±1.5-3.5 mm diam. at base, below inflorescence at once puberulent and strigose with forwardly appressed tapering scaberulous setae to ±1-2 mm, these longer and looser upward, in the inflorescence prolonged into fine flexuous flagelliform tip, the lf-stks strigose like lower stem, the vertically imbricate, sub-concolorous brown-olivaceous, comeous-marginate lfts facially glabrous, appressed-setose-ciliate, the distantly few-capitulate, simple pseudoracemose or weakly branched inflorescence exserted 1-4.5 dm above foliage. Stipules firm erect, lanceolate 4-9 x 1-1.5 mm, dorsally strigose, glabrous within, deciduous before associated lf. Leaf-stalks at and below mid-stem 1-7 cm, at middle (0.6-)0.7-1.3 mm diam., openly sulcate ventrally, the distal ones progressively shorter or subobsolete; pinnae 1-jug., ascending at a narrow angle to vertical, the stout, straight or distally retroarcuate rachis rounded dorsally, acutely keeled and shallowly bisulcate between lfs ventrally, that of larger lvs 7-14 (-16.5) cm, the longer interfoliolar segments (1—) 1.5—3.5(—4) mm; lfts of pinnae at and below mid-stem (45-)50-95-jug., decrescent at both ends of rachis, the moderately unequal first pair 0.5-2 mm distant from subulate paraphyllidia 0.5-1.5 mm, the blades sessile against rachis, in outline narrowly lanceolate or linear-oblong from semicordate base, abruptly apiculate, the longer ones (5—>6—13 x 1.3-2.4(-3) mm, (3.3-)3.5-6 times as long as wide, all smooth veinless above, beneath prominently bluntly 5-7-nerved from pulvinule, the forwardly displaced midrib dividing blade 1:1.5-2.5, shortly branched beyond middle, the anterior and posterior nerves on either side of it produced nearly to blade apex, the outer posterior ones successively shorter, the 1-seriate setae of margin mostly forwardly subappressed and free through 0.5-1.3 mm, but some at times flagelliform, spreading and longer. Peduncles solitary (7-) 10-3 5 mm; capitula globose, without filaments ±9 mm diam., prior to anthesis moriform but commonly involved in extremely fine flagelliform cilia of bracts, these linear-oblanceolate 1.7-3 x 0.3-0.45 mm, glabrous dorsally, ciliate with flexuous setae to 1.5-2 mm; flowers 4-merous 4-androus, some lower ones staminate and shorter; calyx paleaceous, glabrous except sometimes for a basal ring of setae, including the fine setiform fringe 2.2-4.5 mm, 4-cleft well below middle; corolla narrowly funnelform (2.7-)3-4 mm, the thickened cymbiform, dorsally pallid-carinate, externally minutely papillose-puberulent lobes 0.9-1.3 x 0.5-0.8 mm; filaments pink fading whitish, monadelphous through 2-3 mm, exserted 7-9.5 mm, dilated distally. Pods ±2-10 per capitulum, sessile, when 2- or more-seeded oblong in profile 12-20 x 6-7 mm, the replum 0.35-0.6 mm wide, shallowly constricted between seeds, like the valves densely hispid- or silky-setose with forwardly subappressed-ascending scaberulous setae to 1-2 mm, the ripe valves separating from replum and breaking up into free-falling biconvex indehiscent articles 4-6.5 mm long; seeds not seen fully ripe.
Distribution and Ecology - In cerrado on stony soils and in campo rupestre at foot of sandstone outcrops, 1000-1600 m, locally plentiful on Chapada dos Veadeiros within a radius of ±30 km of Alto Paraíso, lat. 13°45'-14°15'S in e.-centr. Goiás, Brazil.—Fl. II-V.
The close relationships of M. venatorum are discussed under M. pyrenea (p. 666) and its differential characters repeated in the Latin diagnosis. Two varieties of the more distantly related M. hypoglauca occur near or within the south periphery of the range of M. venatorum, but are smaller plants (seldom attaining 3.5 dm), with fewer (less than 50) pairs of leaflets per pinna, and geminate peduncles mostly axillary to a coeval leaf. Distribution:Brazil South America
| Goiás Brazil South America